Membrane-type acoustic metamaterial with eccentric masses for broadband sound isolation

Lu, Zhenbo; Yu, Xiang; Lau, Siu‐Kit; Khoo, Boo Cheong; Cui, Fangsen

doi:10.1016/j.apacoust.2019.107003

Cited by 77 publications

(37 citation statements)

References 31 publications

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“…Consequently, membrane displacement and energy transmission are minimised. With an aim to increase the sound attenuating bandwidth, the effects of annular mass loadings and eccentric positioning have been investigated [79]. Some designs have incorporated arrays of membrane meta-units while others have stacked them in series [80].…”

Section: Periodic/lattice Metamaterialsmentioning

confidence: 99%

Additive Manufacture of Small-Scale Metamaterial Structures for Acoustic and Ultrasonic Applications

et al. 2021

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Acoustic metamaterials are large-scale materials with small-scale structures. These structures allow for unusual interaction with propagating sound and endow the large-scale material with exceptional acoustic properties not found in normal materials. However, their multi-scale nature means that the manufacture of these materials is not trivial, often requiring micron-scale resolution over centimetre length scales. In this review, we bring together a variety of acoustic metamaterial designs and separately discuss ways to create them using the latest trends in additive manufacturing. We highlight the advantages and disadvantages of different techniques that act as barriers towards the development of realisable acoustic metamaterials for practical audio and ultrasonic applications and speculate on potential future developments.

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Section: Periodic/lattice Metamaterialsmentioning

confidence: 99%

Additive Manufacture of Small-Scale Metamaterial Structures for Acoustic and Ultrasonic Applications

et al. 2021

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“…The membrane-type resonator's structure can be simplified to a mass-spring model. Within the resonator, evenly biaxial tensile stress is applied to the membrane with the assumption that the stress within the membrane is uniformly distributed [31]. The equivalent stiffness is contributed by tensile stress applied to the membrane.…”

Section: The Modelling Of Bilayer Membrane-type Resonatorsmentioning

confidence: 99%

Study of bandgap property of a bilayer membrane-type metamaterial applied on a thin plate

Gao

Halim

2020

International Journal of Mechanical Sciences

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This work is aimed to study the bandgap property of a thin plate structure with periodically attached bilayer membrane-type resonators. An analytical method based on the Plane Wave Expansion (PWE) method combined with the Rayleigh method, is proposed to predict the bandgap property of bilayer membrane-type metamaterials. The accuracy of the proposed method is verified by the finite element analysis, and a parametric analysis is conducted to reveal the effect of parameters on the bandgap performance. It is found that such a metamaterial can generate two separated bandgaps through the contribution of its two layers of membranes. It is observed that the increase of membrane tensile stress or the magnitude of attached mass can lead to the broadening of bandgaps, whilst the change of unit cell's periodicity has the opposite effect. In addition, if compared with the corresponding single layer membrane-type metamaterials, it is shown that the bilayer membranetype's first bandgap is suppressed while the second one is extended. However, by applying proper membrane tensile stress and mass magnitude, the suppression of the first bandgap can be weakened whilst allowing the tuning of the bandgap location. These characteristics reveal the benefits of using bilayer membrane-type metamaterial as it possesses higher agility in bandgap tuning. The proposed method can provide an effective tool for the bilayer membrane-type metamaterial design and optimisation.

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“…However, the acoustic metamaterials developed so far are mainly effective in blocking low-frequency noise ranging to several Hz, and the sound insulation range is somewhat narrow [14][15][16][17][18][19][20][21][22][23][24][25]. In this work, a hybrid type of sound insulation metamaterials (SIM) was proposed by combining a Helmholtz resonator (600 to 1000 Hz) and space-filling fractal structures (1000 to 1700 Hz) to increase the sound insulation range for covering most of the noise frequency from 600 to 1700 Hz.…”

Section: Introductionmentioning

confidence: 99%

Design of flat broadband sound insulation metamaterials by combining Helmholtz resonator and fractal structure

et al. 2021

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A new sound insulation metamaterial (SIM) is designed by combining a Helmholtz resonator and a fractal structure for sound insulation in the frequency range of 600 to 1700 Hz. Using a fractal-based internal structure, the designed hybrid SIM shows a relatively constant value of sound transmission loss (STL) over the target frequency range. The basic concept of this work is to develop two functional parts working in each effective frequency range. One is a Helmholtz resonance structure that operates with a high value of STL from 600 to 1000 Hz, and the other is an internal fractal structure that shows a high STL at higher frequencies in the 1000 to 1700 Hz range. In this work, the proposed metamaterial has a mean of 16.34 dB with a standard deviation of 1.73 dB within the wide target range of 600 to 1700 Hz. Additionally, the proposed SIM is approximately 40 % smaller in size than the previous resonator and has a higher mean STL with a small ∆STL of 1.7 dB between highest and lowest values.

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Membrane-type acoustic metamaterial with eccentric masses for broadband sound isolation

Cited by 77 publications

References 31 publications

Additive Manufacture of Small-Scale Metamaterial Structures for Acoustic and Ultrasonic Applications

Additive Manufacture of Small-Scale Metamaterial Structures for Acoustic and Ultrasonic Applications

Study of bandgap property of a bilayer membrane-type metamaterial applied on a thin plate

Design of flat broadband sound insulation metamaterials by combining Helmholtz resonator and fractal structure

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